A damaged ACL is often replaced with a graft from a patellar tendon or a semitendinosus tendon. Generally, the patellar tendon graft has small bone pieces attached to its ends, whereas the semitendinosus tendon graft does not. Tunnels are formed in the tibia and femur for use in implanting the graft in the patient's knee. The graft is then secured in the tunnels by fixation means, such as, for example, interference screws or sutures tied to screw posts.